This invention relates to a method for determination of the torque of an internal combustion engine. The invention also relates to a device suitable for determination of the torque.
Torque is a central quantity in drive management in internal combustion engines. For reasons of cost a sensory mechanism is not built into mass-produced vehicles for determination of engine torque. Consequently, the engine timing gear has no remote indication of the torque actually generated by the engine. However, knowledge of engine torque would afford a number of advantages. For example, if torque control could be effected, compensation for disturbance variables could be made by very simple means. Costly control functions in engine management could be replaced by a simple control algorithm.
A process for determining torque, operating processes, and power in internal combustion engines has been disclosed in German patent application DE 44 45 684 C2. The moment of inertia of the rotating masses being taken into account and compensation being made for the torque of oscillating masses, the resulting torque is calculated by means of a characteristic diagram of an engine. This characteristic diagram is determined by experiments at different engine speeds and load stages. The actual torque may then be calculated by means of the characteristic diagram as thus determined on the basis of angular velocity measurements and, after further processing, the fuel-torque pattern is indicated by the crank angle.
Determination of the torque is complicated by various actuating variables depending on the engine and the operating point. These actuating variables must be recognized, allowance must be made for them in suitable form, and compensation must be made for them.